Improvement in devices for heating and feeding air to furnaces



J'. JENKS.

DEVICES FOR HEATING AND FEEDING AIR T0 FURNACES. No.188,914. PatentedMarch 27,1877.

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m fiu'mtor:

",FETERS. FHOTO-LITNOGRAPMEH, WASHINGTON 0 C UNITED STATES JAMES JEN KS,OF DETROIT, MICHIGAN, ASSIG-NOR OF ONE-HALF HIS RIGHT PATENT OFFICE.

TOGEORGE A. JENKS, OF SAME PLACE.

IMPROVEMENT IN DEVICES FOR HEATING AND FEEDING AIR T0 FURNACES.

Specification forming part of Letters Patent No. 188,914, dated March27, 1877; application filed I October 31, 1876.

f coals, are evolved in large volume, requiring the admixture of acorresponding volume of oxygen to secure their combustion.

It is essential that the air-supply be admitted to thecombustion-chamberat an elevated temperature, and herein is the essential feature of myinvention, which consists in the combination of the rear arch,constructed hollow, as shown, and having an atmospheric air-aperture atthe bottom thereof, and the curved flues, built in the sides of thefurnace, with the perforated plates in the sides of thecombustion-chamber above the grate, and the perforated bridge-wall,whereby the air is heated and fed to thecombustion-chamber, as morefully hereinafter explained.

Preferably a perforated grate is used, and in an ash-pit that may betightly closed, as but little air is required to support the preliminarycombustion of the fuel.

Figure 1 is a perspective view of a boiler set in the arch, portions ofwhich are broken out to show the passages. Fig. 2 is a longitudinalvertical section at mm. Fig. 3 is-a cross-section at y y.

In the drawing, A represents the arch, in which the boiler B is set.()is the fire-front, provided with fire and ash-pit doors, adapted to betightly closed, the latter especially,

as it is not necessary to admit much air into the ash-pit to support thepreliminary combustion of the fuel lying on the perforated plate-grateD, behind which is located the bridge-wall E, having a hollow wall orflue, at, extending from end to end, and communicating at the top withthe interior of the furnace through perforations, or through a slot,delivering the air in jets or in a thin sheet.

The rear end wall of the arch is double, forming a chamber, F, intowhich atmospheric air is admitted in proper volume through a door orregister, b, at the bottom. From the top of the chamber F, at each side,a flue, F, is built into the side wall, turning down and extending tothe front on a plane above the grate.

Opposite the furnace, and just above the grate, a perforated plate, G,is set into an opening in the flue, so as to deliver air from the flueinto the side of the furnace in jets, ready to mingle with the gases asthey are evolved from the fuel.

The flue a of the bridge-wall at each end intersects and communicateswith the side lines F.

The natural draft of the furnace causes air to be drawn into the chamberF, where it is highly heated by the flames as they impinge upon itsfront wall, and then pass along through the side lines, where they areheated to a still higher temperature, thence in jets into the furnace,at a temperature considerably above that of the gases, which areignited, upon their admixture with theoxygen.

A portion .of the current of heated air is drawn through thebridge-wallinto the furnace, and ignites any unconsumed gases pass ing over thebridge-wall, thereby insuring a more perfect combustion than it hashitherto been possible to obtain.

There being but little air admitted to the ash-pit to pass up throughthe grate, the latter is liable to burn, to avoid which a small jet ofsteam may be blown into the ash-pit.

the moisture of which steam Will protect the grates.

Ordinary grate-bars may be used, if preferred, but for burning slack orrefuse coal, and similar fuels, the plate-grate is the best adapted.

What I claim as my invention is In a steam boiler furnace, the rearhollow arch A, atmospheric air-aperture b, and curved side flues F, incombination with the side perforated plates Gr, and perforatedbridge-wall a, all arranged as shown, whereby air is heated and fed tothe combustionchamber, substantially as described.

JAMES J ENKS.

Witnesses:

H. F. EBERTS, Wm. P. SPALDING-

